1. Field of the Invention
This invention relates to the art of removing sludge from tanks and particularly deals with a suction cleaner servicing a plurality of tanks having a travelling bridge mounted on top of a tank suspending a plurality of suction heads in the bottom of the tank.
2. Prior Art
Travelling bridge clarifiers are known in the art being disclosed and claimed in our prior U.S. Pat. No. 4,193,871. While these clarifiers had a bridge suspending a plurality of suction heads in a settling tank, the tank was a permanent part of the assembly and was sized and shaped to settle out solids from a pond of liquid that was continuously supplied into one end of the tank with clarified liquid being continuously overflowed from the other end of the tank.
In industry, however, there are many tank installations that have to be periodically freed from sludge deposited in the bottoms thereof without flowing the contents of the tank through a clarifier. For example, in industrial electroplating, phosphating, and etching operations, it is not practical to flow the solutions continuously through a clarifier and the plating and etching tanks accumulate sludge which must be periodically removed to avoid contamination of the products being treated. It would then be an improvement in this art if such tanks could be cleaned with portable apparatus without emptying the tanks or circulating the liquid through separate clarifiers.